Migrate Kart Launch Architecture to Simulation Launches

[zghera]

What is a quick description of the change?

Copy the structure that was implemented in the refactoring of the kart launch files (PRs #4, #6, #7, #9) in the sim launch files to ensure our simulation testing uses the same architecture as our physical kart testing.

Is this fixing an issue?

No

Were any issues created as a result of this change?

#18, Autonomous-Motorsports-Purdue/AMP_ASSv2#25

Are there more details that are relevant?

The problems encountered and their corresponding solutions are listed below

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Problem: The first hurdle to tackle when trying to migrate the kart launch file architecture was that the tfs published by the simulation node, stage_ros , differed from the tfs used in the kart launch files. This would require us to have completely different parameter files for kart and sim launch files. This would lead to a lot of duplication and thus a potentially bigger problem later down the road.
If this discrepancy was purely due to naming, we could simply switch our naming scheme to that of stage_ros'. However, there was a larger issue. In order for the simulation to use as much of the architecture used in the kart launch files, we want laserscan_matcher_node_odom to publish the odom->base_link tf. Additionally, stage_ros, has a duplicate base_link frame, base_footprint, that does not match our architecture.

Solution:

1. The first attempted to solve the problem centered around the use of the node tf_remap. The goal was to try to selectively map the base_link->laserscan_frame to the new tf topic but this was unsuccessful.
2. The second and successful attempt was done by customizing stage_ros to match our architecture. This was completed in Add stage_ros Package #12 and Modify stage_ros Provided Transforms #13.

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Problem: After correcting the tf frame inconsistency, the main error message that occurred when launching sim_autocross_track.launch was:
[ WARN] [..., ...]: TebLocalPlannerROS: trajectory is not feasible. Resetting planner...

Solution:
One suspicion I had to the cause of this issue was the values in the parameter files. So the first rough solution to this was swapping out our move_base.launch import in sim_autocross_track.launch with teb_local_planner's move_base configuration. After some initial success (still some issues --> #18) in simulation, this was deemed to be the cause of the issue.

The param files associated with move_base.launch were modified to (mostly) match teb_local_planner_tutorials' param files as the simulated kart needed to 'fit' on the simulation track we took from teb_local_planner_tutorials. Create Issue Autonomous-Motorsports-Purdue/AMP_ASSv2#25 for determine a way to modify the params to meet our karts physical params while also maintaining our ability to test in simulation.

Check lists (check x in [ ] of list items)

• Test written/updating
• Tests passing
• Coding style (indentation, etc)

No testing needed for launch file development.

Any additional comments?

Moving forward, we should ideally fix the loop closure and any other issues that come up with the simulation that uses the same configuration as our physical launch files so we can use a simulation as close to the physical world as possible. That being said, when table testing occurs, and we need to use a simulation launch file, use the previous launch file (now named sim_autocross_track_only_goal_setting.launch) to avoid issues with the new sim launch.

Resources Used to Inform these Changes:

• ROS Docs
  • http://wiki.ros.org/stage_ros
  • http://wiki.ros.org/tf#tf_remap
• ROS Forums
  • https://answers.ros.org/question/11189/how-to-stop-stageros-from-publishing-its-transforms/
  • https://answers.ros.org/question/175013/removingdeletingignoring-odom-tf-data/
  • https://answers.ros.org/question/216582/how-to-use-tf_remap/
  • https://answers.ros.org/question/11875/set-tf_remap-private-parameters-from-console/

Images to show the differences in the rqt_graph and tf view_frame outputs between the kart and the new sim launch files when trying to migrate the architecture.
OLD Sim

NEW Sim

Kart

1 Lap Run on Autocross Track
https://user-images.githubusercontent.com/39711376/103719064-36eb2180-4f96-11eb-8fd1-d35d772b19ee.mp4

[zghera]

@ihagedo thanks for the approval. Just a heads up for the future, if a PR is in draft status and you are not assigned as a reviewer, you should not give the approval just yet. Thanks!